1. Field of the Invention
The present invention relates to an immobilized fructosyltransferase enzyme and a process for the preparation thereof and more particularly, to a method for the production of an immobilized fructosyltransferase enzyme in which an effective amount of the enzyme obtained from a microorganism which is of the genus Aureobasidium, Aspergillus, Fusarium, or Gloeosporium, is immobilized on an ion-exchange resin carrier, which is a porous or macroporous, basic anion exchange resin, at a pH between about 3 and 8, preferably at a pH between 4 and 6, which may be optionally combined with a bifunctional crosslinking agent and a buffer solution with a concentration in the enzyme solution of 0.01 to 0.1M. preferably 0.025-0.075M and wherein 1 mg of the enzyme protein is suspended in 0.01 to 0.15 milli mol equivalent (hereafter "meq."), preferably 0.025 to 0.1 meq., more preferably 0.05-0.1 meq. of the ion-exchange resin, whereby the immobilized fructosyltransferase enzyme can be used to produce fructooligosaccharide in high yield.
2. Description of the Prior Art
A preferred fructosyltransferase enzyme useful in the practice of the present invention is derived from the genus Aureobasidium, Aspergillus, Fusarium, or Gloeosproium as disclosed in U.S. Pat. No. 4,356,262 and U.K. Patent 2,000,144. Such fructosyltransferase, upon reacting with a sucrose solution, converts the sucrose to fructooligosaccharide. The structure of the fructooligosaccharide is such that 1-4 fructose units are combined with a sucrose at the .beta.(1-2) position of the sugar and its uses include accelerating the activity of Bifidus in the intestines, and use as a sweetening agent which does not readily cause tooth decay, and is low in calories. Fructooligosaccharides have been produced by immobilized fructosyltransferase using the species Polyacrylamide, Carragaenan, or Alginate. However, such immobilization matrices have suffered from many problems such as, for example: (1) It is difficult to retain extracellular enzyme, (2) internal mass transfer resistance is relatively large, (3) the physical rigidity is weak, (4) the matrix itself can be decomposed by microorganisms over a period of time, and (5) it is difficult to mass-produce the bead.
Recently, in an attempt to avoid such problems and disadvantages, the enzyme glucose isomerase was immobilized on a water-insoluble inert carrier to convert glucose into fructose as described in U.S. Pat. Nos. 3,708,397, 3,788,945, 3,850,751, 3,868,304, and U.K. Patent 1,482,122. However, these patents do not disclose the use of an basic, anion-exchange resin having at least 1.0 m.sup.2 /g of internal surface, at least 0.1 ml/g of total porous volume, a radius of 20-2,000 angstroms, and an nominal capacity of at 1.0 meq./g of wet resin for efficiently producing an active and stable fructosyltransferase enzyme.